Rotatable hood assembly



Dec. 14, 1965 J. A. YOUNG 3,223,397

ROTATABLE HOOD ASSEMBLY Filed May 22, 1962 2a F -Z x W F G-l I N VE'N TOR. bid/1E5 ,4. You;

process.

United States Patent 3,223,397 ROTATABLE HOOD ASSEMBLY James A. Young, Alameda, Calif., assignor, by mesne assignments, to Kaiser Industries Corporation, Gakland, Califi, a corporation of Nevada Filed Why 22, 1962, Ser. No. 196,723 2 Claims. (Cl. 266-34) The present invention relates to a rotatable hood arrangement. More particularly, the invention is directed to a rotatable hood arrangement including means to lead exhaust gases away from a refining vessel and means to supply a gas, such as oxygen, to a vessel over which the rotatable hood assembly is disposed. The rotatable hood arrangement of the invention has particular utility when used in conjunction with oxygen steel converters commonly referred to as L-D steel-making facilities.

So-called oxygen steel processes are refining operations wherein oxygen or air enriched in oxygen is blown into a refining vessel to bring about desired oxidation of certain constituents of the metal while at the same time generating sufficient heat for the refining process. Usually a vast amount of heat is generated during this refining The extremely hot gases escaping from the vessel, often combustible, must be taken away with minimum hazard and leakage into surrounding areas. Refining processes of the type described are conducted in batch operations with suitable additions such as hot metal, scrap, ore, flux, etc. being timely made. After a melt has been refined as required, the vessel is tilted to discharge the metal.

The oxygen is introduced into the furnace through one or more oxygen lances of tubular configuration which are made insertable into the furnace for the period of oxygen blow and must be retractable after use so as not to interfere with operation of the furnace. The present invention provides a novel rotatable hood arrangement which comprises hood means and support and guide means. The arrangement is such that the lowermost portion of the hood means can be moved in an arcuate path while the upper end is maintained in contacting relationship with exhaust gas carrying means (which may comprise stack means or a spray chamber, i.e. gas scrubber). Gas introducing means, eg one or more oxygen lances, are operatively associated with the hood means such that the gas introducing means can pass through at least a portion of the hood means so as to be insertable into a metal refining vessel when the rotatable hood arrangement is operatively disposed thereover.

According to the invention, a rotable hood assembly is provided for selectively disposing over the open mouth of a metal refining vessel, such as a converter or the like. The rotatable hood assembly comprises gas receiving means, e.g., stack means, for removal of dust or slag particles as well as gases generated in the refining vessel, and elongated guide means which can support all or part of the weight of the hood means. A hood is dependingly rotatably affixed to the stack means and supported (from above or below the hood) by the guide means. Vertically movable elongated gas introducing means, e.g., oxygen lance, is operatively associated with the hood means and is insertable through a portion of the hood means. The hood means is angularly shaped so that while the upper end remains rotatably aflixed to the stack means, the lower end can swing arcuately from a position over the open mouth of the metal refining furnace to a position which is clear of the furnace, thereby permitting overhead access thereto. The lance which is associated with the swinging hood may move with the hood means. Thus, the lance can be mounted on the hood or simply held by clamps which can align the lance during vertical movement thereof. The stack means may may comprise a spray chamber or an exit duct to carry the flue gases from the furnace to a chamber disposed elsewhere or directly out the stack into the atmosphere. In any case, however, the stack means, e.g. spray chamber or exiting duct, is maintained in a generally fixed position with the hood means dependingly and rotatably affixed thereto.

The invention is further described by reference to the accompanying drawings, wherein:

FIG. 1 is a side view, partially in section, illustrating one embodiment of the rotatable hood assembly according to the invention.

FIG. 2 is a schematic top view of the embodiment shown in FIG. 1 and illustrates the manner in which the rotatable hood assembly can be moved in a horizontal direction.

And FIG. 3 illustrates another embodiment of the attachment between the hood means and the stack means to provide a larger access way for the flue gases to enter the stack means.

As can be seen in FIG. 1, the rotatable hood assembly comprises stack means 10 which is in a generally stationary position and hood means 20 which advantageously comprises a large diameter ducting. The hood means is preferably a water-cooled, steel ducting. Vertically movable, elongated, gas introducing means 30 is extendable through a portion of hood means 20 so as to be insertable into the open mouth of a metal refining vessel 50 when the rotatable hood assembly is selectively disposed thereover.

Hood means 20 is dependingly and rotatably atfixed to the. stack means 10 by supporting rim 16 secured thereto having rollers 18 which roll in a horizontal plane upon guide or platform 22. As can be seen, guide or platform 22 can comprise a right angle flange secured to the internal surface of the stack means 10. A seal 24 can be provided to insure that the particles carried off by the gases evolved from the metal refining vessel will not fall back onto the rollers 18.

As indicated above, stack means 10 may comprise a refractory lined spray chamber. In the embodiment illustrated in FIG. 1 stack means 10 is shown as a spray chamber having refractory lining 12.

Elongated guide means 40 extends in a generally arcuate direction and establishes the path and extent of travel of the hood means 20. Stop means (not shown) can be provided to limit movement of hood 20. Elongated guide means 40 is secured by support beams or the like, not shown, in a fixed position. Hood means 20 is preferably dependingly attached as shown to the elongated guide means 40 by a bracket 42 secured to the hood means and rollers 44 secured to the bracket 42. Rollers 44 are arranged to ride on the flange surface of elongated guide means 40.

Elongated guide means 40 advantageously comprises a simple I beam curved in a generally arcuate path and securely affixed to overhead supports which maintain the elongated guide in fixed position. Rollers 44 attached and secured to support bracket 42 allow the hood means to swing in a generally arcuate path freely. An alternative arrangement is to dispose the elongated guide means so that the hood rests on the guide and is supported on the underside thereof by the elongated guide means maintained in a fixed position. Rollers could be fixed to the guide or to the hood to facilitate rotational movement of the hood.

A lance clamp 32 guides and supports the lance 30 during its vertical movement. Lance clamp 32 is advantageously made a part of bracket 42 so as to provide a unitary structure. A corresponding lance guide 34 is secured to the hood means 20 and guides the lance 30 in a vertical direction through a portion of the hood means. Lance 30 can be actuated at any suitable utility box 36 disposed at any convenient location. The junction box 36 can also cause oxygen to be supplied to the lance 30 for blowing into the metal refining vessel 50. When the lance 30 is in retracted position 30a the hood means may be swung in a horizontal plane away from the vessel 50 to permit charging or access to the open mouth 52 of the vessel. When the hood means is selectively disposed over the open mouth of the vessel 50, lance 30 may be inserted into the vessel 30b for the oxygen blow. After use, the lance can be retracted while the hood is maintained over the mouth of the vessel to receive the dust, particles and flue gases evolved during the refining operation.

The schematic top view in FIG. 2 illustrates generally the positioning of the hood means over the refining vessel and the position it can be moved to when access to the refining vessel is necessary. As can be seen, elongated guide means 40 comprises in part an arcuate segment ending at both sides in a straight line track. The straight line segments may act as stop means to limit rotational movement of the hood. While the embodiment illustrated is shown with a 90 rotation, any desired path may, of course, be provided. Moreover, the configuration of the elongated guide can be established to suit particular requirements. The structure 10, e.g. spray chamber, stack or exit duct, etc. is maintained in a fixed position approximating the center of a circular path traversed by the hood means 20 and the generally arcuate guide means 40.

FIG. 3 describes an alternative manner of attaching hood means 20 to stack means 10. In this embodiment, the attachment is made at the external surface of the stack means rather than at the interior of the stack means as in FIG. 1. The advantage that this embodiment provides is to allow a larger cross-sectional area of flow at the mouth of the stack means so as to provide a minmum of hindrance to the flue gas flow, thereby reducmg the chance of clogging of the passageway by the solids being carried oif in the gases. As can be seen, platform guide 26 is secured to the exterior of the stack means by suitable supports and trusses as shown. The platform guide could, alternatively, be secured to other fixed supports in which case it would not be secured to stack means 10 at all but would simply be adapted to be positioned as illustrated in FIG. 1 with respect to stack means 10. However, in the embodiment shown, supporting rim 28 is secured to the external surface of the hood means at the uppermost end thereof. Supporting rim 28 is similarly provided with rollers 27 to dependingly support the hood from the stack means and allow the rotational movement of hood 20. The free rotational movement of the hood 20 is essential to the successful operation of the invention. By enabling the lower portion of the hood to rotate away from a position over the refining vessel, it is possible to obtain access to the vessel with minimum interference from surrounding structures.

The rotatable hood assembly of the invention is a significant improvement over fixed hood arrangements wherein the converter or refining vessel is removed from the hood position for charging, etc. By allowing the hood to be moved aside, the furnace can be conveniently charged. An additional advantage in avoiding the necessity for undue movement of the refining vessel is in minaddition, moving the rotatable hood assembly away from the mouth will allow access thereto from overhead cranes.

If the oxygen lance is mounted on the hood itself, the use of high overhead lance hoist systems may be dispensed with. In such cases, the lance itself may be removed through the lower end of the hood when the hood is moved away from the furnace. The hood operating mechanism, as well as the lance activator, may be hydraulic, pneumatic or electromechanical, as desired.

While the lower mouth of the hood as illustrated has a bell-shaped mouth, it is noted that various configurations may be employed to insure a relatively unbroken surface to exhaust gases and reduce leakage of the gas to the surrounding area. Moreover, it is possible to employ an attachment at the end of the hood which would be insertable into the open mouth of the refining vessel to insure complete contact thereby substantially precluding gas flow to the surrounding area. It is also possible to provide several hood means rotatable jointly or severally to service a pluarlity of vessels. In this way a number of vessels can be provided with rotatable hoods with maximum utilization of the available area.

It is apparent from the above that various changes and modifications may be made without departing from the spirit of the invention. Accordingly, the scope of the invention should be limited only by the appended claims wherein what is claimed is:

1. A rotatable hood assembly adaptable to be selectively disposed over the open mouth of a metal refining vessel, said assembly comprising stack means having an annular platform mounted at the lower end thereof, elongated arcurate guide means, and hood means; a supporting rim, having rollable elements, secured to said hood means adapted to dependingly and rotatably affix said hood means to said stack means by engagement with said annular platform, said elongated guide means supportingly contacting said hood means, vertically movable, elongated gas introducing means mounted on said hood means and extendable through a portion of said hood means, the lowermost port-ion of said hood means being adapted to traverse a path conforming to said elongated guide means.

2. A rotatable hood assembly adaptable to be selectively disposed over the open mouth of a metal refining vessel, said assembly comprising stack means having an annular platform mounted at the lower end thereof, elongated arcurate guide means, and hood means; a supporting rim, having rollable elements, secured to said hood means adapted to dependingly and rotatably affix said hood means to said stack means by engagement with said annular platform of said stack means, means to dependingly attach said hood means to said elongated guide means, vertically movable, elongated, gas introducing means insertable through a portion of said hood means and adaptable for insertion into the open mouth of a refining vessel when said rotatable hood assembly is operatively disposed thereover, the lowermost portion of said hood means being adapted to traverse a path conforming to said elongated guide means and said gas introducing means being movable with said hood means.

References Cited by the Examiner UNITED STATES PATENTS WHITMORE A. WILTZ, Primary Examiner.

MORRIS O. WOLK,

Examiners.

JAMES H. TAYMAN, JR., 

1. A ROTATABLE HOOD ASSEMBLY ADAPTABLE TO BE SELECTIVELY DISPOSED OVER THE OPEN MOUTH OF A METAL REFINING VESSEL, SAID ASSEMBLY COMPRISING STACK MEANS HAVING AN ANNULAR PLATFORM MOUNTED AT THE LOWER END THEREOF, ELONGATED ARCUATE GUIDE MEANS, AND HOOL MEANS; A SUPPORTING RIM, HAVING ROLLABLE ELEMENTS, SECURED TO SAID HOOD MEANS ADAPTED TO DEPENDINGLY AND ROTATABLY AFFIX SAID HOOD MEANS TO SAID STACK MEANS BY ENGAGEMENT WITH SAID ANNULAR PLATFORM, SAID ELONGATED GUIDE MEANS SUPPORTINGLY CONTACTING SAID HOOD MEANS, VERTICALLY MOVABLE, ELONGATED GAS INTRODUCING MEANS MOUNTED ON SAID HOOD MEANS AND EXTENDABLE THROUGH A PORTION OF SAID HOOD MEANS, THE LOWERMOST PORTION OF SAID HOOD MEANS BEING ADAPTED TO TRAVERSE A PATH CONFORMING TO SAID ELONGATED GUIDE MEANS. 